The eating disorders of anorexia nervosa (AN) and bulimia nervosa(BN) are life-threatening health problems that affect as many as 5 million American females each year. Although a number of psychotherapeutic approaches to treatment have been developed, their effectiveness in producing recovery is low. One limitation of existing treatment approaches is that they tend to focus on altering symptoms of the eating disorders but do not systematically address underlying cause. The intervention program tested in this study is founded on the cognitive approach to the study of the self-concept and an empirically-supported model that suggests that the eating disorders of AN and BN stem from deficits in overall identity development. More specifically, the model suggests that the availability in memory of few positive and many negative self-cognitions and high interrelatedness among the self-cognitions contributes to the disordered attitudes and behaviors associated with AN and BN. A randomized clinical trial will test the effectiveness of a cognitive-behavioral social identity intervention program in fostering development of new and separate positive self- cognitions and promoting recovery from AN and BN. It will further examine the effects of these self-cognition changes on nutritional, psychological and functional health. An experimental pretest-posttest design will be used with supportive psychotherapy as the control intervention. Based on American Psychiatric Association Guidelines, nutritional counseling and medical care components of treatment will be held constant across both experimental and control intervention conditions. The effects of the intervention on self-cognitions, eating disordered attitudes and behaviors, nutritional, psychological and functional health will be monitored pre and post-intervention (immediate, 6 and 12 months post-intervention) in 150 women with threshold and subthreshold levels of AN and BN. The Structured Clinical Interview will be used to establish the eating disorder diagnosis and Ecological Momentary Assessment methodology will be used to prospectively measure eating disorder behaviors. This project extends an established program of research on the role of self-cognitions in emotional and behavioral self-regulation and holds the potential for contributing to the development of an evidence-based psychiatric nursing treatment to promote the recovery of health in women with an eating disorder.